| Title | Strike-Dip Determination of Fractures in Drillcores by an Astatic-Magnetometer |
|---|---|
| Authors | Hayashi, Masao; Furutani, Naoyuki |
| Year | 1982 |
| Conference | Geothermal Resources Council Transactions |
| Keywords | Exploration; Japan; Fukuoka; Geologic Map; Hot Springs; Silica; Drillcores; Fault Zones |
| Abstract | The strike and dip of fractures in drillcores from Well HT-4 drilled din the Hatchobaru geothermal field, Kyushu, Japan, have been determined using as static-magnetometer. Since the drillcores consist mainly of younger andesite lavas, the measurements of the declination and inclination of remnant magnetism should yield the strike and dip of the fractures. The results show that they dip generally southward with angels from 40° to 80° and strike NW-SE or NE-SW The NW-SE trending fractures predominate in the Pleistocene series, which persists at depths shallower that 1000 m, while the NE-SW trending ones occur in the Neogene system at deeper levels, and are considered to be older than the former. The stress field can also be estimated by the strike dip data and the direction of lineation on a slickenside. |